Will I able to recover database completely If I do online file backup(just copy paste of datafiles) while database or running or daily disk backup while database is running?
If I force checkpoint and take file system backup when no activity which is as good as hot backup mode backup ..correct? Is there a way Oracle can restore using DUL tools?
Onetime I was able to clone database when source database is running with NOARCHIVELOG mode.
Is there a way Oracle peope can restore using DUL tools or someother tools?
You may try PRM-DUL can be download here
https://s.dbrecover.com/dbrecover-for-oracle-latest-dist.zip
DBRECOVER Recovery Options
For Oracle incidents, start with the DBRECOVER for Oracle trial to verify table visibility, row previews, and export readiness on copied datafiles. For MySQL and InnoDB incidents, DBRECOVER for MySQL is free software and can inspect.ibd files, ibdata1, and database directories locally.
When the case is urgent, preserve the original files first, work from copies, and contact paid emergency support with the database version, platform, error messages, file list, and recovery objective.